Well circulation tool

ABSTRACT

A tool for automatically maintaining adequate circulation of drilling fluid in a well hole when a pressure kick is encountered. The tubular body section of the tool has a channel for fluid which extends through the side wall to the outside. Inside the body section there is a previously set operable member which normally covers the channel and blocks the flow of fluid from the tool into the well hole. When the drilling bit encounters a zone of high pressure which causes backward flow of fluid and brings on the likelyhood of plugging of the fluid discharge orifices of the bit, the preset member is operated by an associated check valve which responds to the back flow. The channel in the wall of the tool is thus automatically uncovered so that fluid can flow into the well hole from a source other than the drilling bit.

Oliver [451 Apr. 9, 1974 I WELL CIRCULATION TOOL [75] A Inventor: Don L. Oliver, Houston, Tex.

[73] Assignee: Cities Service Oil Company, Tulsa,

Okla.

[22] Filed: Aug. 31, 1972 [21] Appl. No.: 285,175

[52] U.S. Cl. 175/318, 175/320 [51] Int. Cl E2lb 41/00 [58] Field of Search 175/231, 232, 235, 237, 175/241, 242, 317, 318, 320

[56,] References Cited UNITED STATES PATENTS 2,239,586 4 1941 Appleby 175/317 3,025,919 3/1962 Angel et a1. 175/317 1,619,328 3/1927 Benckenstein 175/317 X 2,046,798 7/1936 Thrift 175/318 X 2,128,352 8/1938 Creighton... 175/318 X 2,307,658 1943 Appleby 175 317 2,596,832 5/1952 Williams 175/318 X 3,369,619 2/1968 Brown 175/317 3,409,078 Knox et al. 175/318 X 3,667,557 6/1972 Todd et a1. 175/318 X Primary Examiner-David H. Brown Attorney, Agent, or Firm-Elton F. Gunn [5 7] ABSTRACT A tool for automatically maintaining adequate circulation of drilling fluid in a well hole when a pressure kick is encountered. The tubular body section of the tool has a channel for fluid which extends through the side wall to the outside. Inside the body section there is a previously set operable member which normally .covers the channel and blocks the flow of fluid from valve which responds to the back flow. The channel in the wall of the tool is thus automatically uncovered so that fluid can flow into the well hole from a source other than the drilling bit.

10 Claims, 1 Drawing Figure WELL CIRCULATION TOOL BACKGROUND OF THE INVENTION This invention pertains to the drilling of wells, more particularly deep wells, and especially petroleum wells wherein drilling fluid is pumped down a rotating drilling string to and through a drill bit. This results in circulation of the drilling fluid from the top of the well hole to, the bottom and then back to the surface.

As is well known, the reason for circulating drilling fluid during a rotary drilling operation is to, cool the bit, wash away drill cuttings, and lubricate the string as it runs in the hole. Should the fluid discharge orifices of the bit become even partially plugged, adequate circulation of the fluid can be lost. As a consequence the beneficial functions of fluid circulation are also lost or else seriously impaired. Plugging of the bit can be dangerous, especially in the event of an unexpected pressure kick which occurs when a high pressure zone is penetrated, or when attempting to kill a kick which has already occurred, since the ability to control pressure at the bottom of the hole is lost if pumping of drilling fluid to the well hole cannot be adequately maintained. In suchinstances total or partial plugging of the bit results from-the pressure of the kick being higher than the pressure of the drilling fluid in the drilling string, i.e. there is a backward flow of fluid-entrained materials into the bit and these materials become jammed in the fluid orifices.

Prior methods of restoring adequate circulation of drilling fluid after plugging of the bit include making a round trip to replace the bit or perforating the drilling string above the bit by shooting while the string is still in the hole. Since it is not practical to trip the string out of the hole until the kick is killed, it has been necessary to perforate rather than making a trip, but this requires preparation and lowering of a shot into the string. This consumes valuable time in an emergency situation and affords little control over the degree of perforation and, hence, the resulting pressure which will be required to restore adequate circulation. As a consequence, a need was recognized for a method which can be employed for restoring adequate circulation of drilling fluid to a bore hole after plugging of the bit, and preferably, to restore adequate circulation without substantially changing the pressure required to pump the fluid.

SUMMARY OF THE INVENTION It is therefore an object of this invention to provide a method for quickly restoring adequate circulation of drillingfluid to a bore hole after the drilling bit has become plugged. 1

Another object is to restore adequate circulation of drilling fluid to a bore hole following plugging of the bit without substantial change in the pumping pressure required to achieve the circulation.

Still another object is to improve safety of the drilling operation when a kick is encountered.

Other objects and advantages of the invention will become apparent from the following description and the appended claims.

The present invention is a drilling tool which can be used in combination with other members of a drilling string to automatically feed drilling fluid into a well hole from a source other than the drilling bit. The tool is activated when a high pressure zone is penetrated The tool comprises a tubular body section having threads at each end which are connectible to members of a well drilling string. A longitudinal passageway extends through the body section for conveying fluid received from the string. At least one channel for fluid extends through the side wall of the body section from the passageway therein to the outside. There is a previously set operable member inside the body section which normally covers the channel through the wall, and which uncovers the channel when operated. The purpose of the preexisting but normally covered channel is to provide a duct through which fluid being pumped can be diverted to the well hole in the event that adequate circulation cannot be maintained after partial or total plugging of the drilling bit following a pressure kick. Whether plugging of the bitactually occurs or not, the possibility thereof is compensated for automatically by a flow responsive means which operates the preset member. The fluid channel through the wall of the tool is thus automatically uncovered upon backward flow of fluid in the passageway of the body section. 1 v

The operable member can be a sleeve contiguous with the wall of the fluid passageway in the body section and slidable in the passageway both over and beyond the opening of the fluid channel through the wall of the body section. Sliding of the preset sleeve to uncover the channel can be effected by means of an at- BRIEF DESCRIPTION OF THE DRAWINGS The drawing depicts a partly sectional view of one embodiment of the present invention and is intended to illustrate the invention without limiting the same.

DESCRIPTION OF PREFERRED EMBODIMENTS The circulating tool is generally represented at 1, being connectedat the upper end to a drill pipe 2 and to a drill bit 3 at the lower end. The tubular body section 4 of the tool is threadedat each end for connection with the bit 3 and a coupling 5 on the drill pipe. A passageway 6 for fluid extends through the body section of the tool, being interconnected with fluid passageways 6a and 6b which, respectively, lead from the drill pipe 2 and into orifices3a in the drill bit. Drilled channels 7 for fluid extend transversally through the wall 8 of the body section and thus lead from the passageway 6 to the outside.

Channels 7 are ducts which extend through the wall 8 of the body section so that drilling fluid being pumped into passageway 6 can be discharged out into a well hole from a source other than the drilling bit. During normal drilling operations these channels are covered over by an impervious slidable sleeve 9 which is axially aligned in the passageway 6 and is contiguous therewith. The sleeve is chamfered on the outside at the lower end to provide a shoulder 10.

The wall of the body section which defines the passageway 6 is recessed to accomodate the thickness of the sleeve, thus tending to preserve the diameter of the passageway while also providing a lower stop 1 1 for the sleeve. The sleeve is thus held up in the normal preset position over the channels 7 by the abutment of the sleeve shoulder 10 against the lower stop.

A ball valve, generally represented at 12, is located in passageway 6b in the lower end of the body section of the tool. The ball valve comprises an annular ball seat 13 which is screwed onto the lower end of the sleeve 9, a ball 14 which fits into the seat, a cage 15 for maintaining the ball in alignment with the seat, and a helical spring 16 which urges the ball upwardly into the seat 13 when there is no flow of fluid through passageway 60 of the sleeve.

Transversally cut slots 17 extend through the wall of the sleeve toward the center line. When the sleeve is in the normal, preset position as shown in the drawing, the slots 17 are below the fluid channels 7. However, when the sleeve is operated, i.e. moved upward by backward flow against the closed ball valve, the slots 17 then line up with the channels 7 so that pumped fluid can flow out of sleeve passageway 60 into a well hole.

During normal drilling operations mud is pumped in the forward direction through the drill string and into the well hole, i.e. through passageways 6a, 6, 60, 6b and the bit orifices 3a. This holds the sleeve 9 down against the stop 11, keeping channels 7 covered over, and holds the ball valve open by urging the ball away from the valve seat so that the drilling fluid can pass to and through the orifices 3a of the bit.

When there is no flow-of drilling fluid through the tool in the forward direction, the ball valve snaps closed, but there is no upward movement of the sleeve 9. Raising of the sleeve is effected when forward flow stops and there is backflow of fluid into the bit through orifices 3a. More specifically, the ball 14 instantly moves into the seat 13 when forward flow ceases, being urged by spring 16. With the bottom of passageway 60 effectively sealed off by means of the ball, the assembly in effect becomes a piston, and is displaced upward by pressure resulting from backflow into the orifices 3a. As previously indicated, upward movement of the sleeve effects alignment of the slots 17 with channels 7 so that drilling fluid can flow out of the tool into the hole being drilled.

Means can also be included for holding the sleeve up so that the channels 7 and the slots 17 remain aligned in the event that pressure in passageway 6b eases down after elevation following a backflow into the bit. Such can occur when the bit has become substantially but not completely plugged, and in which case recovering of the channels with the sleeve would be undesirable since adequate flow of fluid through the bit alone could not be maintained. The drawing shows use of a snap ring and recess arrangement for holding up the sleeve after it has been operated. More specifically, a snap ring 18 fits into a groove around the circumference of the sleeve and is normally fully depressed into the groove by the wall of the passageway 6 when the sleeve is in the lower, preset position over the channels. Higher up in the passageway 6 there is a groove 19 around the circumference thereof. When the sleeve moves upward to the extent that ring 18 becomes aligned with the groove 19, the ring snaps partially open, thus engaging the groove and latching the sleeve to the passageway. The channels 7 and the slots 17 are thus maintained aligned until the sleeve is deliberately pushed back down and reset. If desired, the sleeve can be reset while the tool is in the well hole by lowering a weight on a wire line to bump the sleeve downward.

Provisions can also be included for manually raising the sleeve by an action taken at the surface in the unlikely event that it is not automatically operated during a pressure kick. The drawing illustrates use of a latch 20 for this purpose, the latch being attached to the sleeve by means of a bar 21 which extends across the passageway 6c of the sleeve from one side to the other. To raise the sleeve, a tool can be lowered through the drill pipe on a wire line, thus engaging the latch 20 so that the sleeve can be pulled upward. Upon further tugging of the wire line the tool can be disengaged from the latch and retrieved.

Where preferred, the upper part of the sleeve 9 which covers the channels and the lower chamfered part which is attached to the ball valve do not have to be integral, i.e. they can be two separate parts while still having the configuration and arrangement shown in the drawings.

Since one object of the invention is to be able to maintain adequate flow of drilling fluid to a well hole after the bit has become plugged, the channel in the wall of the body section of the tool should have an open area at least equal to the total open area of the drilling fluid orifices in the bit As shown in the drawing, the body section of the tool can be provided with at least one other channel which is covered over when the sleeve is preset and which is uncovered when the sleeve is operated. In such a case the total open area of all of the channels should at least about equal the total open area of the fluid orifices in the drilling bit.

When using an apparatus as shown in the drawing, several of the features shown are optional, examples being the previously described snap ring arrangement for securing the sleeve above the channels, the ball cage 15 and the spring 16. The walls of the passageway 6b can serve as guides for directing the ball into the valve seat, and backflow of fluid can be relied upon to move the ball into the seat. In addition, check valves other than a ball valve can be used for operating the sleeve, e.g. a swing check or disc check valve can be suitably adapted to the purpose.

While the present invention has been described with reference to specific conditions, apparatus components and arrangements thereof, it will nonetheless be understood that still other embodiments will become apparent which are within the spirit and scope of the invention which is defined in the following claims.

What is claimed is:

1. A well drilling tool comprising:

a. a tubular body section having threads at each end which are connectible to members of a drilling string,

b. a longitudinal fluid passageway through the body section,

c. a fluid channel which extends through the side wall of the body section from the fluid passageway therein to the outside.

d. a previously set operable member inside the body section which normally covers the fluid channel through the wall of the body section when set and which uncovers the channel when operated, and

e. flow responsive means for automatically operating the previously set member and uncovering the fluid channel upon backward flow of fluid in the passageway of the body section of the tool, said flow responsive means including a ball check valve which is open during flow of fluid through the passageway of the body section in a forward direction and which is closed during flow of fluid in the passageway in a backward direction, the previously set member being operable by movement thereof beyond the fluid channel, and being urged to move beyond the channel upon backward flow of fluid against the ball check valve when it is closed.

2. Apparatus as in claim 1 wherein the operable member is a sleeve contiguous with the wall of the passageway in the body section, the sleeve being slidable in the passageway both over and beyond the opening of the channel through the wall of the bodysection.

3. The apparatus of claim 2 wherein the ball check valve is attached to the sleeve.

4. Apparatus as in claim 2 and further comprising latching means for securing the sleeve in a position beyond the channel after the operative movement of the sleeve.

5. Apparatus as in claim wherein the sleeve is located in the fluid passageway of the body section toward the end thereof into which fluid is introduced in the forward direction and thecheck valve is located in the fluid passageway toward the other end of the body section.

6. Apparatus as in claim 5 and further comprising a drilling pipe attached to the end of the-body section into which drilling fluid is fed in the forward direction I and a drilling bit having drilling fluid orifices attache to the other end of the body section.

7. Apparatus as in claim 6 wherein the open area of the fluid channel in the wall of the body section is at least about equal to the total open area of the drilling fluid orifices in the drilling bit.

8. Apparatus as in claim 6 and further comprising at least one other channel in the wall of the body section which is covered over when the sleeve is preset and which is uncovered when the sleeve is operated, and wherein the total open area of all of the fluid channels in the body section is at least about equal to the total open area of the fluid orifices in the drilling bit.

9. A well drilling tool comprising:

a. a tubular body section having threads at each end which are connectible to members of a drilling 6 string, b. a longitudinal fluid passageway through the body section,

0. a fluid channel which extends through the side wall of i the body section from the fluid passageway therein to the outside,

d. a previously set operable sleeve member located in said passageway in the body section toward the end thereof into which fluid is introduced in the forward direction and wherein the sleeve normally covers the fluid channel through the wall of the body section when set and which uncovers the channel when operated, said sleeve member being I contiguous with the wall of the passageway in the body section and slidable in the passageway both over and beyond the opening of the channel through the wall of the body section,

e. flow responsive means for automatically operating the previously set member and uncovering the fluid channel upon backward flow of fluid in the passageway of the body section of the tool, said flow responsive means including a check valve which is open during flow of fluid through the passageway of the body section in a forward direction and which is closed during flow of fluid in the passageway in a backward direction, the previously set member being operable by movement thereof beyond the fluid channel, and being urged to move beyond the channel upon backward flow of fluid against the check valve when it is closed, said check valve being located in said fluid passageway toward the other end of the body section from which said sleeve member is located, a drilling pipe attached to the end of the body section into which drilling fluid is fed in the forward direction, a drilling bit having drilling fluid orifices attached to the other end of the body section, and wherein the open area of the channel in the wall of the body section is at least about equal to the total open area of the drilling fluid orifices in the drilling bit.

10. Apparatus as in claim 9 and further comprising at least one other channel in the wall of the body section which is covered over when the sleeve is preset and which is uncovered when the sleeve is operated, and wherein the total open area of all of the fluid channels in the body section is at least about equal to the total open area of the fluid orifices in the drilling bit. 

1. A well drilling tool comprising: a. a tubular body section having threads at each end which are connectible to members of a drilling string, b. a longitudinal fluid passageway through the body section, c. a fluid channel which extends through the side wall of the body section from the fluid passageway therein to the outside, d. a previously set operable member inside the body section which normally covers the fluid channel through the wall of the body section when set and which uncovers the channel when operated, and e. flow responsive means for automatically operating the previously set member and uncovering the fluid channel upon backward flow of fluid in the passageway of the body section of the tool, said flow responsive means including a ball check valve which is open during flow of fluid through the passageway of the body section in a forward direction and which is closed during flow of fluid in the passageway in a backward direction, the previously set member being operable by movement thereof beyond the fluid channel, and being urged to move beyond the channel upon backward flow of fluid against the ball check valve when it is closed.
 2. Apparatus as in claim 1 wherein the operable member is a sleeve contiguous with the wall of the passageway in the body section, the sleeve being slidable in the passageway both over and beyond the opening of the channel through the wall of the body section.
 3. The apparatus of claiM 2 wherein the ball check valve is attached to the sleeve.
 4. Apparatus as in claim 2 and further comprising latching means for securing the sleeve in a position beyond the channel after the operative movement of the sleeve.
 5. Apparatus as in claim 2 wherein the sleeve is located in the fluid passageway of the body section toward the end thereof into which fluid is introduced in the forward direction and the check valve is located in the fluid passageway toward the other end of the body section.
 6. Apparatus as in claim 5 and further comprising a drilling pipe attached to the end of the body section into which drilling fluid is fed in the forward direction and a drilling bit having drilling fluid orifices attached to the other end of the body section.
 7. Apparatus as in claim 6 wherein the open area of the fluid channel in the wall of the body section is at least about equal to the total open area of the drilling fluid orifices in the drilling bit.
 8. Apparatus as in claim 6 and further comprising at least one other channel in the wall of the body section which is covered over when the sleeve is preset and which is uncovered when the sleeve is operated, and wherein the total open area of all of the fluid channels in the body section is at least about equal to the total open area of the fluid orifices in the drilling bit.
 9. A well drilling tool comprising: a. a tubular body section having threads at each end which are connectible to members of a drilling string, b. a longitudinal fluid passageway through the body section, c. a fluid channel which extends through the side wall of the body section from the fluid passageway therein to the outside, d. a previously set operable sleeve member located in said passageway in the body section toward the end thereof into which fluid is introduced in the forward direction and wherein the sleeve normally covers the fluid channel through the wall of the body section when set and which uncovers the channel when operated, said sleeve member being contiguous with the wall of the passageway in the body section and slidable in the passageway both over and beyond the opening of the channel through the wall of the body section, e. flow responsive means for automatically operating the previously set member and uncovering the fluid channel upon backward flow of fluid in the passageway of the body section of the tool, said flow responsive means including a check valve which is open during flow of fluid through the passageway of the body section in a forward direction and which is closed during flow of fluid in the passageway in a backward direction, the previously set member being operable by movement thereof beyond the fluid channel, and being urged to move beyond the channel upon backward flow of fluid against the check valve when it is closed, said check valve being located in said fluid passageway toward the other end of the body section from which said sleeve member is located, f. a drilling pipe attached to the end of the body section into which drilling fluid is fed in the forward direction, a drilling bit having drilling fluid orifices attached to the other end of the body section, and wherein the open area of the channel in the wall of the body section is at least about equal to the total open area of the drilling fluid orifices in the drilling bit.
 10. Apparatus as in claim 9 and further comprising at least one other channel in the wall of the body section which is covered over when the sleeve is preset and which is uncovered when the sleeve is operated, and wherein the total open area of all of the fluid channels in the body section is at least about equal to the total open area of the fluid orifices in the drilling bit. 